The present invention relates generally to multifunctional testing of materials. More particularly, the present invention relates to the testing, processing, and process monitoring of materials used in the manufacture of integrated circuit chips for the semiconductor and optoelectronic industry.
With the impetus toward smaller and faster devices, semiconductor manufacturers increasingly require rapid discovery and implementation of new materials capable of providing greater performance, such as low k, high k, copper and other novel materials. However, several of these new materials are sensitive to oxidation at elevated temperatures, and additionally are prone to emit volatiles and particulates or exhibit property changes upon heating and cooling.
Thus, these new materials require testing to determine their usefulness in semiconductor processing. Conventionally, the processing, testing, and process monitoring of the thermal-mechanical properties of thin film materials requires the use of several complementary tools, each having a single function. Thus, several such tools are required to monitor the physical, chemical, or electrical properties of sample materials undergoing temperature changes. No single tool has conventionally been able to change functions to monitor, analyze and quantify multiple properties simultaneously during processing, especially thermal cycling.
Therefore, characterizing the stress hysteresis, thermal stability, out gassing, film shrinkage, thermal expansion coefficients, adhesion, and electrical properties of materials, where the data base is nonexistent or limited, conventionally requires the use of several complementary tool sets and the use of multiple samples. However, the use of several separate tools for testing, as is conventionally required, often introduces inconsistencies and errors in test results.
One error introduced when using separate testing tools is sample-to-sample error. Often a sample material is destroyed during testing. Thus, several identical samples are typically required since several separate tools are utilized for testing. Theoretically each tool tests the properties of an identical sample, with the results from the separate tools being correlated to determine the characteristics of the material. However, difficulties arise in creating xe2x80x9cidenticalxe2x80x9d samples, resulting in non-identical samples. Hence, each tool actually tests a different sample material, resulting in testing errors and error accumulation during later correlation of the data.
Another error introduced when using several separate testing tools is tool-to-tool errors. When testing different properties of a material with different tools, theoretically the engineer sets the testing environments for the various tools similarly, then tests the properties for which each particular tool is designed. However, as with creating xe2x80x9cidenticalxe2x80x9d material samples, problems arise when attempting to set xe2x80x9cidenticalxe2x80x9d testing environments on separate testing tools. Often the heating temperatures do not exactly match on different tools, or heating times may not be the same. In either case, testing is actually performed in non-identical testing environments, resulting in testing errors and error accumulation during later correlation of the data.
Thus, conventional material testing is greatly susceptible to errors because of the combined effects of errors caused by sample-to-sample variation and errors caused by tool-to-tool variation. Moreover, new material samples are often in limited quantity resulting in process conditions often being unrepeatable. Often, correlation of the various results to form a meaningful understanding of the problem at hand is next to impossible.
In view of the above, what is needed is a method and apparatus for testing materials wherein sample-to-sample error and environment-to-environment error can be reduced. The method should further enable a faster testing cycle, and allow for easy correlation of test results.
The present invention addresses the above mentioned needs by providing an integrated, multifunctional annealing system. The invention provides a system for monitoring, obtaining, and measuring physical characteristics of thin film materials. The system involves simultaneous scanning of the material with physical sensors, such as laser beams, and probes by proximity or contact, and correlating the obtained data to provide a database of thin film characteristics over time, temperature changes, and varying environments.
In one embodiment, an apparatus for simultaneously extracting multiple physical characteristics of materials is disclosed. The apparatus includes a housing and a chamber disposed within the housing that is capable of achieving multiple temperatures. At least two material characteristic sensors are also disposed within the housing for providing multiple sets of data concerning the characteristics of a sample material. Finally, a data correlator coupled to the sensors correlates the first and second sets of data. Advantageously, the apparatus of the present invention reduces sample-to-sample error and tool-to-tool error encountered in conventional material characteristic testing.
In another embodiment, a method for simultaneously extracting and analyzing physical characteristics of materials is disclosed. The method comprises providing a housing and a chamber disposed within the housing that is capable of achieving multiple temperatures. A first set of physical properties of a sample material is then sensed using a first sensor disposed within the housing. Next, a subsequent set of physical properties of the sample material is sensed using a different sensor disposed within the housing. Finally, the sets of physical properties are correlated, thus determining the material characteristics of the sample material.
Because thin film materials are oxidation sensitive, the process monitoring and testing of these films requires heating or annealing in a very low or no oxygen environment that is currently difficult to achieve with traditional high temperature stress tools. Advantageously, the present invention addresses this issue by being capable of operating in a controlled inert gas environment or an ultra high vacuum environment, thus making possible simulation of actual thermal processing. A further advantage of the present invention is its suitability for thermal desorption spectroscopy. Further, the chamber""s circular highly reflective and controlled cooling walls allow radiant heat from a heating lamp source to be focused uniformly onto the sample material.